Rachel_Jones
Say hello to the latest addition to my loving microbiology home, Staphylococcus aureus. But you can call her Golden staph for short. The 'aureus' in her name refers to the Latin language, translated to 'golden' in English. My child can do no harm.... well, most of the time.
When I say our love goes skin deep, I mean it literally and figuratively. She spreads her love via hugs or even handshakes! (any skin-to-skin contact really...). She can make you sick if you're not careful, you know how children can be!
Look at her glow! She gets her pigment from Staphyloxanthin which is a carotenoid pigment. Staphylococcus aureus' golden pigment impairs neutrophil killing and promotes virulence through its antioxidant activity. She is round with a skinny diameter of 1-4mm and a sharp boarder. She is convex - in shape ;).
The golden pigment imparted by carotenoid pigments is the eponymous feature of the human pathogen Staphylococcus aureus. Here we demonstrate a role of this hallmark phenotype in virulence. Compared with the wild-type (WT) bacterium, a S. aureus mutant with disrupted carotenoid biosynthesis is more susceptible to oxidant killing, has impaired neutrophil survival, and is less pathogenic in a mouse subcutaneous abscess model. The survival advantage of WT S. aureus over the carotenoid-deficient mutant is lost upon inhibition of neutrophil oxidative burst or in human or murine nicotinamide adenine dinucleotide phosphate oxidase–deficient hosts. Conversely, heterologous expression of the S. aureus carotenoid in the nonpigmented Streptococcus pyogenes confers enhanced oxidant and neutrophil resistance and increased animal virulence. Blocking S. aureus carotenogenesis increases oxidant sensitivity and decreases whole-blood survival, suggesting a novel target for antibiotic therapy.
The pathogenesis of staphylococcal infections is multifactorial. Golden pigment is an eponymous feature of the human pathogen Staphylococcus aureus that shields the microbe from oxidation-based clearance, an innate host immune response to infection. Here, we screened a collection of S. aureus transposon mutants for pigment production variants. A total of 15 previously unidentified genes were discovered. Notably, disrupting metabolic pathways such as the tricarboxylic acid cycle, purine biosynthesis, and oxidative phosphorylation yields mutants with enhanced pigmentation. The dramatic effect on pigment production seems to correlate with altered expression of virulence determinants. Microarray analysis further indicates that purine biosynthesis impacts the expression of ∼400 genes involved in a broad spectrum of functions including virulence. The purine biosynthesis mutant and oxidative phosphorylation mutant strains exhibit significantly attenuated virulence in a murine abscess model of infection. Inhibition of purine biosynthesis with a known small-molecule inhibitor results in altered virulence gene expression and virulence attenuation during infection. Taken together, these results suggest an intimate link between metabolic processes and virulence gene expression in S. aureus. This study also establishes the importance of purine biosynthesis and oxidative phosphorylation for in vivo survival.
Staphyloxanthin is a carotenoid pigment that is produced by some strains of Staphylococcus aureus and is responsible for the characteristic golden color that gives S. aureus its species name. Staphyloxanthin also acts as a virulence factor. It has an antioxidant action that helps the microbe evade death by reactive oxygen species produced by the host immune system.
The ability of Staphylococcus aureus to adhere to the extracellular matrix and plasma proteins deposited on bio-materials is a significant factor in the pathogenesis of orthopedic-device related infections. S. aureus possesses many adhesion proteins on its surface, but it is not known how they interact with each other to form stable interactions with the substrate.
Staph bacteria can live harmlessly on many skin surfaces, especially around the nose, mouth, genitals, and rectum. If the skin is punctured or broken, however, staph bacteria can enter the wound and cause many kinds of infection, some of them serious and even deadly.
